A variety of static mixer types exist for mixing together multiple components of a fluid flow received from fluid cartridges, such as side-by-side fluid cartridges, or similar dispensing devices. Generally, conventional mixers mix the components of the fluid flow together by continuously dividing and recombining the components in an overlapping manner. This mixing is achieved by directing the fluid components along a mixing component structure that includes a series of mixing elements (also referred to as “mixing baffles”) of alternating geometry. Such division and recombination creates alternating layers of the fluid components. In this manner, the streams of the fluid components are progressively thinned and diffused, thereby creating a generally homogenous mixture of the fluid components at the mixer outlet. While such mixers are generally effective to mix a majority of the mass of the incoming fluid components, mixers are often subject to a streaking phenomenon in which streaks of one of both of the fluid components are left completely unmixed in the final mixture extruded at the mixer outlet.
The mixing element arranged at the inlet end of a mixer is generally referred to as an entry mixing element, or initial mixing element, and it provides some initial division of the incoming fluid flow directed into the static mixer. The effectiveness of conventional entry mixing elements in providing a degree of initial mixing sufficient to mitigate streaking is dependent upon proper rotational alignment of the entry mixing element relative to a transverse flow cross-section of the incoming fluid flow. For example, FIG. 1A shows a conventional mixing component 1 and its entry mixing element 2 positioned in a non-optimal rotational orientation relative to a transverse flow cross-section of an incoming fluid flow containing fluid component 3 (the other component(s) not being shown). As shown in FIG. 1A, the fluid component 3 is not fully divided by the entry mixing element 2, thereby resulting in undesired streaking of the fluid component 3 in the mixture extruded at the mixer outlet. By comparison, FIG. 1B shows the mixing component 1 and its entry mixing element 2 positioned in an optimal rotational orientation relative to a transverse flow cross-section of the incoming fluid flow, such that fluid component 3 is divided into at least first and second portions and streaking in the extruded mixture is thereby substantially averted.
For many static mixers, the mixer conduit includes an integrally formed nut for threadedly attaching the mixer to a fluid cartridge or similar dispensing device. As the mixer is threaded onto the cartridge, the mixing component often rotates with the mixer conduit relative to the cartridge. Thus, the final rotational orientation of the mixing component relative to the fluid outlets of the cartridge, and thus to a transverse flow cross-section of the fluid flow to be mixed, is dependent on the degree to which the user tightens the mixer onto the cartridge. Different users, or even the same user, may rotate a particular mixer to inconsistent final rotational orientations when tightening the mixer. Consequently, and undesirably, mixing performance of the entry mixing element may vary significantly from user to user, and even from use to use by the same user.
Accordingly, there is a need for improvements to known entry mixing elements and corresponding static mixers that address these and other shortcomings of known entry mixing elements and static mixers.